It is often desirable to present the programme of a project in the form of a bar chart, and when the critical path and floats have been found by either the arithmetical or computer methods, the bar chart has to be drawn as an additional task. (Most computer programs can actually print a bar chart but these often run to several sheets.)
As explained in Chapter 30, bar charts, while they are not as effective as networks for the actual planning function, are still one of the best methods for allocating and smoothing resources. If resource listing and subsequent smoothing is an essential requirement, graphical analysis can give the best of both worlds. Naturally, any network, however analysed, can be converted very easily into a bar chart, but if the network is analysed graphically the bar chart can be 'had for free', as it were.
Modern computer programs will of course produce bar charts (or Gantt charts) from the inputs almost automatically. Indeed the input screen itself often generates the bar chart as the data are entered. However, when a computer is not available or the planner is not conversant with the particular computer program the graphical method becomes a useful alternative.
The following list gives some of the advantages over other methods, but before the system is used on large jobs planners are strongly advised to test it for themselves on smaller contracts so that they can appreciate the short-cut methods and thus save even more planning time.
1 The analysis is extremely rapid, much quicker than the arithmetical method. This is especially the case when, after some practice, the critical path can be found by inspection.
2 As the network is analysed, the bar chart is generated automatically and no further labour need be expended to do this at a later stage.
3 The critical path is produced before the floats are known. (This is in contrast to the other methods, where the floats have to be calculated first before the critical path can be seen.) The advantage of this is that users can see at once whether the project time is within the specified limits, permitting them to make adjustments to the critical activities without bothering about the non-critical ones.
4 Since the results are shown in bar chart form, they are more readily understood by persons familiar with this form of programme. The bar chart will show more vividly than a printout the periods of heavy resource loading, and highlights periods of comparative inactivity. Smoothing is therefore much more easily accomplished.
5 By marking the various trades or operational types in different colours, a rapid approximate resource requirement schedule can be built up. The resources in any one time period can be ascertained by simply adding up vertically, and any smoothing can be done by utilizing the float periods shown on the chart.
6 The method can be employed for single or multi-start projects. For multi-project work, the two or more bar charts can (provided they are drawn to the same time and calendar scale) be superimposed on transparent paper and the amount of resource overlap can be seen very quickly.
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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.