Construction Management, Accounts & Enterpreneurship Devlopment (General Engineering) (SSC JE)

Functional organization–
• The functional organization was evolved by F.W. Taylor while he was working as a foreman. He suggested eight foremen, four infector and four in planning division as under.

Heny Gantt–He created Gantt charts that are used in major infrastructure project.
• M.R. Walker and J.E. Kelley jointly developed a project management technique called the critical path method (CPM).

Note–PERT (Program Evaluation Review Technique), a methodology developed by U.S. Navy in the 1950s.

Milestone Chart–
• The modern requirement for proper control of the work, various improvements are made in it from time to time.
• The improvement over the Gantt-bar chart is milestone chart or milestone system.
• In this system the various sub-works or events are shown by squares instead of bars of Gantt bar chart.

The critical activity has zero float.
• In CPM analysis there are three types of activity based on their float.

1. Sub-critical activity–Sub-critical activities are those activities that are occurring earlier than the scheduled time.
• Sub-critical activity has a positive float.
• Sub-critical activity have more than sufficient resources.

2. Critical activity–Critical activity are those activity that are occurring just on time.
• The critical activity has zero float
• Critical activity has just sufficient resources.

3. Super critical activity–Super critical activities are those activities that are occurring later than the scheduled time.
• Super critical activity has negative float.
• Super critical activities have less than sufficient resources.

There are following guidelines for the construction of a network diagram.
1. Each activity is represented by one and only one arrow in the network.
2. Dummy activity consumes no time or resources.
3. The network should be drawn such that all activities are completed to reach end objective.
4. Arrows should not cross each other, if crossing in unavoidable then bridging may be done.

Bar chart/Gantt chart
• Bar chart is graphical representation of activities vs. time.
• Here time duration is marked on x-axis.
• Activities are marked on y-axis.
• From the above Gantt chart, it is clear that
horizontal lines, which are show the activity of the project.
• The beginning and end of each bar represent
starting and finishing times of a particular activity respectively.
• The length of the bar, the time required for completion.
Limitation of bar chart–
1. Lack of degree of detail
2. A bar chart is unable to depict the interdependencies of various activities clearly.
Note : The commission has accepted option (c) as correct.

The critical path network helps an engineers–
(1) To concentrate his attention on critical activities.
(2) To divert the resources from non-critical advanced activities to critical activities. (3) To be cautions for avoiding any delay in the critical activities to avoid delay of the whole project.
Note : The commission has accepted option (b) as correct.

CPM–
1. Deterministic approach
2. Activity oriented
3. Single time estimate (τ₀, τₚ and τₘ,)
4. A method to control cost and time 5. Normal distribution 6. Concept of float

PERT–
1. Probabilistic approach
2. Even oriented
3. Three time estimate
4. A technique of planning and control of time
5. -distribution
6. Concept of slack

The particular task performance in CPM is known as activity.• Activity is represented by an arrow in a network diagram.
• Activity is task that consumes both time and resources.
• A dummy activity is represented by dotted arrow and it does not consume time and resource.

Project size is important factor that can affect the accuracy and efficiency of estimates. As size increase the interdependency among various element of the software grows rapidly.
• The degree of structural uncertainty also has an effect on estimation risk.