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2. The Management Process Objective:

Provide an overview of the key elements of the construction project management process, and identify the various roles of the critical path method (CPM) within this process.

Summary: 2.1 Stages of Planning 2.2 Elements of the Construction Project ____ ___

Management Process 2.3 The Role of Critical Path Method (CPM) in ___ the

Management Process

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2.1 STAGES OF PLANNING

Planning of a project is necessary from its inception through to its completion.

The nature of the planning and its objectives depend on the party and the stage of the project.

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Planning should be implemented as a cyclical process, using feedback of the latest information to improve the plan.

PLAN &

Fig. 2-1: Cyclical Nature of Planning

MONITORWORK IN PROGRESS

EVALUATE PLAN

MODIFY PLAN

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• Design Stage Planning.

• This is aimed at providing a facility that will meet the owners objectives (delivery date, life-cycle cost, functionality, and aesthetics).

• Generally the responsibility of the owner’s management representatives.

• It will include comparing the efficacy of alternative solutions.

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• In the earliest stages, the project will lack detailed definition and be subject to radical change.

• As the project becomes more precisely defined, the planning and analysis of the project will become correspondingly more detailed.

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• Bidding/Negotiation Stage Planning.

• Planning at this stage is essentially the responsibility of the contractor.

• It is used primarily to establish a price for the work, but also to compare and justify the adoption of alternative solutions where negotiation is available.

• Often, contractors will be required to produce a detailed plan of work (in particular a CPM schedule) as part of their bid submission.

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• Construction Stage Planning.

• Planning at this stage is extended to include:– monitoring and control of work in progress;

– re-plan for changes to the work; and

– plan remedies to problems.

• It is performed by the contractor and by management representatives of the owner.

• Its primary objective is to ensure that the project is built as required and, by the contractor, to fine tune the construction process to maximize profits.

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• At the most general level, planning in the construction stage is used to:

– identify longer term problems (is work falling behind schedule),

– establish general courses of action to be taken (eg: remedial action and procurement of certain resources), and

– communicate actual and projected progress to senior management.

• Detailed planning, on the other hand, is used to:– establish a precise account of work completed and costs

incurred (for the purposes of payment, assessing changes, establishing claims etc.),

– provide a more accurate assessment of the schedule of work and resource demand, and

– communicate work to be performed to site-level management.

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• Greater accuracy and detail in the information available during the construction stage facilitates a more accurate assessment of the resources required and the relative merits of alternative approaches.

• Detailed planning cannot be projected far into the future since it is more prone to uncertainties.

• A plan for the construction work should not be considered a static entity. The management process should facilitate a regular modification of the plan.

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2.2 Elements of the Construction Project Management Process

Effective management of a project involves:

– identification of the objectives, work, constraints, and environmental conditions of the project;

– organization of the work and the resources to achieve the stipulated objectives within the constraints and environmental conditions; and

– monitoring and control of work in progress to identify and remedy problems in a timely manner, and for general accounting purposes.

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• Resources:

Resources need to be– scheduled and allocated to the various tasks; and– an accurate account of their usage needs to be

maintained.

There will be much interdependence between the resources. Eg:– increasing the numbers of laborers employed

may increase expenditure and affect space requirements.

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The primary construction resources are:

– Time. Time is a scarce resource, spent in the execution of the various construction tasks. Concerned with:

• periods of time required to perform work and employ resources, and

• timing of events such as delivery and completion dates.

– Money. Both expenditure and income are of concern in terms of actual sums exchanged over time.

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– Personnel.

• Management. Managers/supervisors are a scarce resource. Demand, availability, specialties, performance and experience are of prime concern.

• Labor. Skilled and unskilled labor will usually be hired as required. Demand, availability, skills, performance and experience are of prime concern.

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– Equipment. Demand, availability, types, performance, operator experience, and operating space are of prime concern. May be:

• owned (in which case it is clearly a scarce resource possibly to be allocated among competing tasks) or

• rented/leased (in which case availability and delivery dates are of importance)..

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– Materials. This includes both raw materials and prefabricated components. Delivery dates and storage space requirements are of prime concern.

– Information. This includes items such as working drawings, rebar bending schedules, etc. Supply dates are of prime importance.

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– Space. This is used for:

• access, the execution of processes, placement of temporary and permanent structures, and the storage of materials and equipment.

• It is dynamically variable in that its availability and usage will vary as the project progresses. Its location, extent, form, and availability are of prime concern.

– Subcontractors. A subcontractor’s time of arrival on site, and the facilities and space requirements, for example, are of prime concern.

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• Objectives:

These can be divided into:

– Primary objectives. Those that ultimately need to be achieved in the execution of the project, eg:

• meet the completion date;

• minimize project cost;

• maximize quality and safety;

• minimize inconvenience to the public.

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– Subobjectives. Those that should be achieved as an integral part of meeting the primary objectives, eg:

• maximize production rates;

• minimize material wastage;

• maximize equipment utilization;

• minimize interference between processes.

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Typically, in construction, we have multiple objectives such as the need to minimize both costs and project duration.

– Such objectives can be conflicting, for example, reducing the project duration can increase costs.

– In these situations, some strategy needs to be adopted, such as prioritizing satisfaction of the objectives.

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Objectives involve optimization or satisficing:

– optimization: where an attempt is made to find the overall best solution, eg:• to reduce costs as far as possible;• to make the demand for labor as constant as possible.

– satisficing: where an attempt is made to achieve a specific goal, eg:• completing the project by a given date;• ensuring that there is sufficient space to operate a given item of equipment.

Objectives that require satisficing are arguably a form of constraint.

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A decision concerning one resource often affects one or more other resources. Eg:

– reducing the time to complete work may increase costs;

– reducing vigilance on site safety can ultimately increase costs; and

– an item of equipment which increases production rates for the task to which it is allocated may cause interference with other tasks reducing their performance.

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The primary objectives in construction are:

– Time:

• Events. Eg:– to satisfice target dates, perhaps with some contingency to allow for possible

delays.

• Periods. Eg:– to minimize the time required to complete the project, perhaps by parallelizing

activities;– to minimize the time required to complete individual tasks, perhaps by crashing;– to maximize activity float (slack) to provide flexibility in scheduling for a

smooth resource demand and as a contingency against delays.

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– Money. The project should be organized to ensure that expenditures and income follow an acceptable profile for all parties:

• Expenditure. To be minimized, and incurred as late as possible or at least when can be afforded.

• Income/Profits. To be maximized and received as soon as possible.

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– Quality. A certain minimum standard of workmanship/design should be achieved to ensure:

• the satisfactory performance of the facility;

• prevent rework/redesign; and

• maintain reputation.

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– Safety. There is a humanitarian and legal duty to minimize the occurrence and significance of accidents. There is also an economic argument since accidents result in:

• increased insurance premiums;• downtime;• low motivation;• equipment repair;• facility reconstruction; and • poor reputation, others???.

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– Interference. Construction work can interfere with the activities of third parties.

• Eg: resurfacing a road will cause delays to traffic.

• Where important, work needs to be organized in a manner that minimizes such interference.

– Production Rate. Subobjectives. Eg:

• maximize rate of execution of a task to minimize the period of its interference with other activities; and

• satisfice a given production rate to ensure that the task is completed before a certain deadline.

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– Personnel. Subobjectives.

• Management. Managers/supervisors need to be allocated to projects/operations, in accordance with their expertise.

• Labor. A reasonably level demand for employment of labor should be maintained to minimize idle time and prevent large demand fluctuations on support facilities and support staff.

– It is preferable not to reallocate crew members and move crews between different tasks unnecessarily since this destroys learning effects.

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– Equipment. Subobjectives. Eg:

• maximize equipment utilization to maintain cost effectiveness (such as balancing numbers of excavators and dump-trucks); and

• minimize interference between equipment and with other processes.

– Materials. Subobjectives. Eg:

• to minimize wastage;• satisfice supply dates; and• minimize space utilization.

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– Space. Subobjectives. Eg:

• minimize access distances;

• satisfice safe distances for hazards;

• satisfice storage requirements for materials and equipment;

• satisfice space requirements for processes; and

• minimize interference between processes.

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• Constraints and Environmental Conditions:

Constraints and environmental conditions affect the way in which work may proceed.

Constraints introduce factors to the project that should not be violated.

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Constraints may be hard or soft:

– hard constraints are those that must be met precisely, eg:• it is not possible to surface a road until the base has been constructed.

– soft constraints are those that include an element of flexibility . eg:

• concreting work should stop when temperatures fall below a certain value - work would not stop immediately but rather at a convenient juncture.

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The primary constraints and environmental factors in construction are:

• Activity Precedence.

– Certain activities must precede others either for logical reasons or because they share a limited resource.

– Delays between the start of activities, and between the finish of one activity and the start of another may also be required.

– These constraints are typically resolved by establishing an activity network diagram.

– No false dependencies between activities should be built into these diagrams since it will reduce the ease with which other objectives (such as minimizing project duration) can be achieved.

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• Time. Certain activities must, for example, be completed before a deadline.

• Money. The availability of finances, for example, may vary during the course of a project and affect the acquisition of resources.

• Space. The location and amount of space available may affect decisions concerning:

– storage,

– temporary structures,

– execution of processes (need space for processes),

– access to the site (this may affect the types of component that can be delivered).

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• Personnel. There will be a limited number of qualified managers/supervisors available, and there may be limits on the number of laborers that can be accommodated on site at any time.

• Equipment. Certain items of equipment may, for example, have limited availability, affecting the scheduling of tasks competing for their use.

• Materials and Components. Delivery dates, for example, may affect the time at which certain tasks can commence.

• Information. Supply dates of information may affect the time at which some resources can be ordered and certain tasks can commence.

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• Legal and Regulatory. For example:

– tasks such as hammer-piling may not be able to proceed after specified hours for noise abatement reasons; and

– some activities must follow stipulated procedures to minimize pollution or satisfy safety requirements.

• Environment. The methods adopted and the scheduling of activities can be affected by:

– weather, – temperature, and – ground conditions, and others???

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2.3 The Role of the Critical Path Method (CPM) in the Management Process

By far the most widely used and broadest scope tool in construction project management is the Critical Path Method (CPM).

CPM provides a formal framework for establishing, representing, and controlling the work involved in a project in both qualitative and quantitative terms.

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• The specific applications of CPM are:

• An identification of the relative ordering and precedences among the activities in graphical form (the activity network). This can:

– provide insight; and– suggest ways of rearranging work (maximizing parallelism) to reduce

project duration and provide extra flexibility in scheduling.

• Determination of the overall project duration, and intermediate milestones.

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• An identification of the times at which activities are scheduled to start and be completed.

• An identification of the critical activities which:

– if delayed will extend the duration of the project, and

– if crashed will reduce the duration of the project.

• An identification of the float (slack or leeway) on activities.

– Float provides a buffer in case of delays.

– Float can be used to reschedule activities in a way that provides a smooth demand for resources and minimizes conflict for use of scarce resources.

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• A framework for:

– user/automated reduction of project duration at minimal extra cost;

– smoothing of resource demand; and

– minimizing conflicting demand for scarce resources.

• A framework for scheduling subcontractors, labor, equipment, and material delivery.

• A basis for comparing alternative methods and resource combinations in terms of project duration and cost.

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• A mechanism for communicating information to personnel (such as the plan and progress).

• A mechanism for recording progress and comparing with the plan to identify problems.

• A tool for assessing the effects of changes and delays, and evaluating remedial actions.

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• Advanced and future developments of CPM include:

• Evaluating uncertainty in both activity durations and resource requirements (stochastic methods).

• Handling fuzzy constraints (such as resource requirements, and deadlines).

• Site space management.