Example Using Manual Techniques

An example of how the duration of a small project can be reduced quite significantly using manual techniques is shown by following the stages of Figure 26.13. The project involves the installation of a pump, a tank and the interconnecting piping which has to be insulated. Figure 26.12 shows the diagrammatic representation of the scheme which does not include the erection of the pipe bridge over which the line has to run. All the networks in Figure 26.13

Figure 26.12 Pipe bridge

Bar Chart

 ABODE E,ecl»Q L3VQ Tesl 3 2 2 4 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 , A ! Days p3y "'esl 1 1 O^fO^O I E I C D1 t D2 T I D11 I D3 | @ I E I B V f D2 4 E2 Erect Weld JL Test & f \ Pump^/^ \ JT > Pipe w ( AlnsuT / > Uvv~~^^'"T^/T^vj I E1 | ® I E2 ,

Figure 26.13 Small pipeline project are presented in activity on arrow (AoA), activity on node (AoN), and bar chart format, which clearly show the effect of overlapping activities. Figure 26.13(a) illustrates all the five operations in sequence. This is quite a realistic procedure but it takes the maximum amount of time - 16 days. By erecting the tank and pump at the same time (Figure 26.13(b)) the overall duration has been reduced to 14 days. Figure 26.13(c) shows a further saving of 3 days by erecting the pipe over the bridge while also erecting the pump and tank, giving an overall time of 11 days. When the pipe laying is divided into three sections (D1; D2 and D3) it is possible to weld the last two sections at the same time, thus reducing the overall time to 10 days (Figure 26.13(d)). Further investigation shows that while the last two sections of pipe are being welded it is possible to insulate the already completed section. This reduces the overall duration to 8 days (Figure 26.13(e)).

It can be argued, of course, that an experienced planner can foresee all the possibilities right from the start and produce the network and bar chart shown in Figure 26.13(e) without going through all the previous stages. However, most mortals tend to find the optimum solution to a problem by stages, using the logical thought processes as outlined above. A sketch pad and pocket calculator are all that is required to run through these steps. A computer at this stage would certainly not be necessary.

It must be pointed out that although the example shown is only a very small project, such problems occur almost daily, and valuable time can be saved by just running through a number of options before the work actually starts. In many cases the five activities will be represented by only one activity, e.g. 'Install lift pump system' on a larger construction network, and while this master network may be computerized, the small 'problem networks' are far more easily analysed manually.

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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