Time Scaled Networks And Linked Bar Charts

When preparing presentation or tender documents, or when the likelihood of the programme being changed is small, the main features of a network and bar chart can be combined in the form of a time scale network, or a linked bar chart. A time scale network has the length of the arrows drawn to a suitable scale in proportion to the duration of the activities. The whole network can, in fact, be drawn on a gridded background where each square of the grid represents a period of time such as a day, week or month. Free float is easily ascertainable by inspection, but total float must be calculated in the conventional manner.

By drawing the activities to scale and starting each activity at the earliest date, a type of bar chart is produced which differs from the conventional bar chart in that some of the activity bars are on the same horizontal line. The disadvantage of such a presentation is that part of the network has to be redrawn 'downstream' from any activity which changes its duration. It can be seen that if one of the early activities changes in either duration or starting point, the whole network has to be modified.

However, a time scale network (especially if restricted to a few major activities) is a clear and concise communication document for reporting up. It loses its value in communicating down because changes increase with detail and constant revision would be too time consuming.

A linked bar chart is very similar to a normal bar chart, i.e. each activity is on a separate line and the activities are listed vertically at the edge of the paper. However, by drawing interlinking vertical (or inclined) dummy activities to join the main bars, a type of programme is produced which clearly shows the interrelationship of the activity bars.

Chapter 21 describes the graphical analysis of networks, and it can be seen that if the ends of the activities were connected by the dummies a linked bar chart would result. Figure 22.10 shows a small time scale network and Figure 22.11 shows the same programme drawn as a linked bar chart.

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Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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