Site Supervision�&�Operations

Dr Adewale Abimbola, FHEA, GMICE

aabimbola@cavc.ac.uk

Aim and Objectives

Aim: Construction Planning Techniques

Objectives: At the end of the lesson, the students should be able to:

• Discuss the detailed considerations in master programme preparation.
• Compare different techniques for planning resources: bar chart & network.

Learning Outcomes and Assessment Criteria

P5. Describe the key principles of construction project management.

M3. Compare different techniques for planning and managing resources.

INTRODUCTION - THE PRINCIPLES OF CONSTRUCTION PLANNING���

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• Why is planning important in construction?
• Planning for construction projects and controlling costs and schedules are often challenging and require a thorough understanding of construction management techniques to bring the project to a successful conclusion.
• Project management is essentially about delivering the right thing at the right cost on time. This seems simple, as there are many factors to consider, but achieving all the project objectives can be complex.

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Figure 1. Iron triangle — triple constraints of project management (Dhillon, 2018).

Contract, or Master, Programme

• This is produced, following the build-up of operational duration and development of a programme calculation sheet.
• This programme will be used on site to progress the works and hence there is no room for major errors or anomalies – it must be an accurate and realistic representation of the anticipated construction activity.
• The most important task of site management is to ensure that the contract period does not exceed the time given in the tender and, ideally, a shorter contract duration is desirable.
• The sequencing of construction operations is largely the product of experience. Critical operations will be determined in the method statement and these set the framework within which all other operations must be programmed.
• Contract planning does not finish once the contract, or master, programme is implemented at the commencement of the siteworks but, rather, the programme serves as a basis for progress monitoring control techniques used during the course of the project – short-term planning.

Figure 2. An example of a contract, or master, programme (March, 2017).

Build-up of Operational Duration for Contract Programmes

• The build-up of programmes, or determining the duration of construction operations, is a process of establishing the quantity of work involved in each item, determining the time required to complete the item by considering the labour and plant needed, and depicting the calculated duration on the programme.
• The quantity of work is easily ascertained from the bill of quantities or by measuring from the drawings.
• Determining the time required to undertake an operation is a more complicated matter. There are, principally, two ways in which the labour and plant rates needed to make the calculation for durations can be acquired. These are:

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1) From experience: the contractor will, over the years and from many projects, build up a library of information based on experience and feedback of data, such that labour and plant work rates, or outputs, often referred to as ‘constants’, are known.

2) From building price books: these present labour and plant constants for many operations in all fields of construction,

• It is essential that estimators and planners build up a library of programming information because the accuracy and value of programmes is mainly dependent on the accuracy of the constants used in the build-up.

Check the Appendices for some build-up calculations.

Preparation of a Contract, or Master, Programme

Figure 2. An example of a contract, or master, programme (March, 2017).

Preparation of a Contract, or Master, Programme

Preparation of a full working contract, or master, programme for a building project involves detailed consideration of the following tasks:

1. abstract quantities from the bill of quantities
1. The volume of work for each operation is abstracted from the bill of quantities (Fig. 3).
2. Items may be summarised under the subheadings of building element, e.g. groundworks, etc. e.g. excavate oversite to reduce levels.
3. This follows the rules in the New Rules of Measurement.
4. It may also be necessary to measure quantities from the drawing to ensure that the full volume and location of the work in any item are accurately determined.

Figure 3. An example page of an abstract of quantities used in the preparation of a contract programme (March, 2017)

Preparation of a Contract, or Master, Programme

Preparation of a full working contract, or master, programme for a building project involves detailed consideration of the following tasks (cont’d):

(ii) develop a method statement

• The method statement follows the format of a simple spreadsheet and presents information in columns, typically under the headings of: operation number; operation (description); method (of construction); plant (requirements); labour (requirements); and remarks (Fig. 4).

Figure 4. An example page of a method statement used in the preparation of a contract programme (March, 2017).

Preparation of a Contract, or Master, Programme

Preparation of a full working contract, or master, programme for a building project involves detailed consideration of the following tasks (Cont’d):

(iii) compile a programme calculation sheet

• A spreadsheet format is used, arranging information under the headings: operation number; task reference; operation (description); quantity; unit; constant (work output); hours (computed); weeks (converted); labour gang (make up); plant (type specified); net duration; and remarks (Fig. 5).

Figure 5. An example page of a programme calculation sheet used in the preparation of a contract programme (March, 2017).

(Check Appendices for some build-up calculations).

Preparation of a Contract, or Master, Programme

Preparation of a full working contract, or master, programme for a building project involves detailed consideration of the following tasks (cont’d):

(iv) draw up a contract, or master, programme

• The Gantt, or bar, chart is the most commonly used technique for presenting programmes (Fig. 2).
• Computer-derived programmes are more sophisticated and they show critical and non-critical operations, duration floats (leeway in criticality of sequence), and resource levelling (balancing).

Figure 2. An example of a contract, or master, programme (March, 2017).

Preparation of a Contract, or Master, Programme

Preparation of a full working contract, or master, programme for a building project involves detailed consideration of the following tasks (cont’d):

(v) Consideration of short-term programming

• Short-term programming is particularly applicable to complex construction projects where programmes are, for ease in use, subdivided into section programmes and where the duration of some operations are so long that an element of planning throughout their duration must take place.

(vi) Profiling the labour and plant requirements

• In fig. 6, a vertical block bar chart is used to depict the labour requirements for principal building elements, while the plant requirement over the contract is shown by means of a bar (horizontal) chart. Any preferred format of presentation may be adopted.

Figure 6. An example of a resource programme (March, 2017)

Construction Planning Techniques

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Construction Planning Techniques

Planning Techniques: Bar Charts�

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• Bar charts are the most commonly used method of planning for all stages of the planning process and on projects both small and large.
• The most common bar chart used in construction is the Gantt Chart which is a visual presentation of the sequence of construction events.
• While simple bar charts depict operations and their durations, more sophisticated charts will show breakdowns of key construction operations into sub-operations, non-productive periods during the contract such as holidays.

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Figure 7. Example bar chart showing simple resource deployment information (March, 2017).

Planning Techniques: Gantt Charts��

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• The work programme can also be utilised to manage materials, regarding when they need to be ordered and how much they have used.
• The site management team can look at the chart and can quickly tell from looking at the chart if work is keeping scheduling or falling behind and compress the remaining activities in the project to ensure that the project is completed on time.

What the advantages and disadvantages?

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Construction Planning Techniques – Network Analysis

• Network analysis is a useful construction planning method which allows interrelationships of operations to be clearly shown.
• Networks are often presented as one of two types: as ‘arrow diagrams’ or as ‘precedence diagrams’ (Figs. 8 & 9).
• The two methods essentially achieve the same goal, but with different means of depicting the information.
• For site use the network is usually converted into a bar chart which is used for short-term control and shows operations at scheduled times.

Figure 8. Nomenclature for compiling an arrow network diagram (March, 2017).

Figure 9. Nomenclature for compiling a precedence network diagram (March, 2017).

Planning Techniques – Program Evaluation and Review Technique (PERT)

PERT is a network analysis technique used to estimate project duration when there is a high degree of uncertainty about the individual activity duration estimates.

PERT uses probabilistic time estimates.

• Duration estimates based on using optimistic, most likely, and pessimistic estimates of activity durations, or a three-point estimate.
• PERT attempts to address the risk associated with duration estimates by developing schedules that are more realistic.

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PERT weighted average =

optimistic time + (4 X most likely time) + pessimistic time

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Example:

PERT weighted average =

8 + (4 X 10) + 24 = 12 days

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where optimistic time= 8 days, most likely time = 10 days, & pessimistic time = 24 days

Therefore, you would use 12 days on the network diagram instead of 10 when using PERT for the above example.

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Example 1 – PERT

Using the information in the table below;

1. Find the expected duration of each activity
2. Construct the project network
3. Find the critical path and expected project completion time.

All time in weeks.

Example 1 – Solution

1. Find the expected duration of each activity

All time in weeks.

Example 1 – Solution

Construct the project network

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Example 1 – Solution

Find the critical path and expected project completion time.

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Example 1 – PERT

1. You calculate the expected duration of each activity
2. Then, you construct the project network
3. And determine the critical path and expected project completion time.

Self-assessment Task 1 - PERT

Using the information in the table below;

1. Find the expected duration of each activity
2. Construct the project network
3. Find the critical path and expected project completion time.

All time in days.

Self-assessment Task 2 - PERT

Using the information in the table below;

1. Find the expected duration of each activity
2. Construct the project network
3. Find the critical path and expected project completion time.

All time in days.

Critical Path

• The identification of the critical path regarding the construction of any project is a vital element in its success.
• The critical path is the longest sequence of activities, which must be completed on a due date.
• An activity on the critical path cannot be started until its predecessor activity is complete, if there is a delay, the entire project will be delayed.

Programme Float

• The concept of float is used to describe the amount of time that an event or activity can be delayed without delaying the overall completion of the works. Float is calculated by subtracting the time necessary to perform a work activity from the time available to perform it.
• Only activities which are not on the critical path can have a float. Identifying a float can be helpful allocating resources, to sub-contractors when they are behind on program, where priority can be given to activities with less available float.

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Planning Techniques: Critical Path Method (CPM)

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Planning Techniques: Critical Path Method (CPM)�

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• The critical path method is used on the network diagram to determine the longest path through the network.
• All the tasks on this path are considered critical, that is, they cannot be late, or the overall project will be late.
• The project team should know which tasks are on the critical path, so they can always be given the necessary attention to keep the project on track.
• To identify the critical path forward and backward passes are undertaken.
• Automated tools simplify critical path calculations, eliminating the manual process.
• Project scheduling software automates critical path calculations, simplifying the entire process.
• Understanding the Critical Path Method and its automated calculations is integral for effective project management and timely project delivery.

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Example 2

• Using the information in the table below;
• Construct the project network or logic.
• Determine the expected project completion time.
• Find the critical path.

Example 2: Solution

• 1) Construct the project network or logic.

Example 2: Solution

• 2) Find the expected project completion time.
• Complete the forward pass to determine the project completion time of 53 days.

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Example 2: Solution

• 3) Find the critical path.
• Complete the backward pass to confirm the project completion time and determine critical path.

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Self-assessment Task 3 – CPM

• Using the information shown in the table to;
• Calculate the expected project completion time.
• Find the critical path.

Self-assessment Task 4 – CPM

• Using the information shown in the table to;
• Calculate the expected project completion time.
• Find the critical path.

Similarities – PERT & CPM

Major Difference – PERT & CPM

References/Bibliography

• CMS Group (2023) The 8 RIBA stages explained. Available at: https://cms-group.co/the-8-riba-stages-explained/ (Accessed: 17 January 2026)
• Dhillon, H. (2018) Iron Triangle — Triple Constraints of Project Management. Available at: https://medium.com/@harpreet.dhillon/iron-triangle-triple-constraints-of-project-management-e818e631826c (Accessed: 17 January 2026)
• March, C. (2017) Construction management – theory and practice. London: Routledge.
• Morton, R. (2002) Construction UK: Introduction to the industry. Oxford: Blackwell Science.
• Praxis Framework Limited (2023) Line of balance. Available at: https://www.praxisframework.org/en/library/line-of-balance (Accessed: 04 June 2025)
• Zornes, T. (n.d.) Critical path method (cpm). Available at: https://sixsigmastudyguide.com/critical-path-method-cpm/ (Accessed: 03 June 2025).

Calculating Durations for Labour Inputs to the Programme

Example

Suppose a bricklayer had to build a one-brick thick (215 mm) wall, 20 metres long by 3 metres in height. How long would this take?

Solution

Volume of work: 20 X 3 = 60 m^2

60 m^2 of 215 mm brickwork = 7,200 bricks approx. qty

[For a one-brick wall, 1 m2 = 120 bricks (Flemish or English bond)]

A bricklayer can lay 50 bricks per hour (Labour constant)

Therefore, Volume of work (qty)/work output = 7,200/50 = 144 hours

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Convert the rate into unit of measure used on the programme, i.e. week (40 hours).

Therefore, duration = 144 / 40 = 3.6 weeks for one operative

In simplified term, the duration would be 0.9 weeks for a gang of 4 operatives.

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The constitution of the work gang, i.e. the ratio, in a situation such as that given, would be 4 to 1 or 4 to 2 depending on the requirements of the work, where one or two general operatives are deployed to assist the four trade operatives.

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Appendix A

Calculating Durations for Plant Inputs to the Programme

Example

Suppose an operation involves excavating 5000 m^3 of spoil with an excavator performance output of 25 m^3/hr (constant). How long would this take?

Solution

Machine output = Volume of excavated material / total plant hours

Therefore constant = Volume/duration

Or

25 = 5000 / duration

Duration = 5000/25 = 200 machine hours

Convert the rate into unit of measure used on the programme, i.e. week (40 hours)

Therefore,

Duration = 200 / 40 = 5 weeks

Appendix B

Calculating Durations for Plant Inputs to the Programme

Example

Suppose the same excavating operation as before, i.e. 5000 m^3 of spoil, is to be excavated in 20 working days. What is the required machine output to achieve this?

Solution

Total plant hours = 20 (days) X 8 (hours/day) = 160 hours

Therefore required output is = Volume of excavated material / total plant hours

= 5000 / 160 = 32 m^3 per hour.

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Example

Suppose an excavator with an output of 36 m^3 per hour is being used and the spoil must be removed by lorries with 3 m^3 capacity to a spoil tip with a 20 minute cycle time. How many lorries will be required?

Solution

Number of lorries = cycle time / loading time

Loading time = machine output / capacity = 36 /3 = 12 lorry loads/hour or 5 mins loading time

Therefore,

Number of lorries = cycle time / loading time

= 20 mins / 5 mins = 4 lorries

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The cycle of operations involve the time taken to load the lorry; and the time taken to travel to the tip, off-load and return – for the four lorries over a one-hour cycle.

Appendix C