Resource Management
6. Based on full knowledge of the disadvantages and advantages of different organizations, one can select
5.7 Allocate Resources to Project Plan
5.7.1 Example
We will use the same example as discussed previously in Chapter 4 for the time management. The project is to install a mechanical pack- age and connect it with piping as shown in Table (5.1). From this table we can define the relationship between the project activities.
Figure (5.6) shows the critical path of this project through the project plan. Table (5.2) shows the time frame for each activity.
This is presented in the table by the total floating time (TF). The resources column indicates the number of personnel required for each activity per day. The last column shows the total number of days required for each activity. Thus, for example, in Table (5.2) excavation needs 7 workers per day, and work will last for 8 days, so this activity needs 56 working days in order to be achieved.
Figure (5.6) shows the distribution of time duration of this proj- ect, which is 25 days. Summing the total working days, shown in Table (5.2), the effort will actually consume 173 working days.
Table 5.1 Example for foundation Item
100 200 300 400 500 600 700 800
Activity Mobilization
Excavation
(Pouring concrete foundation and piping support)
Install the piping
Install the mechanical package Put the grouting
Connect the piping
Commissioning and start up
Time (Days)
3 8 10 4 1 1 5 2
Precedence Activity
- 100 200,100 300,100 300 300,500 400,500 700
0 100 3 Mob. 0 3 3
3 200 11 Excavate 3 8 11
11 300 21 Pouring concrete 11 10 21 3 400 7 Install piping 14 4 18 Figure 5.6 Preceding diagram define the critical path.
21 500 22 Mech. package 21 1 22
22 600 23 Put grouting 22 1 23 7 700 12 Conn. Piping 18 5 23
23 800 25 Comm.& Start up 23 2 25
Table 5.2 Resources allocated to the activities No. 100 200 300 400 500 600 700 800
Activity Mobilization Excavation Pouring concrete foundation and piping support Install piping Install the mechanical package Put the grouting Connect the piping Commissioning and start up
D 3 8 10 4 1 1 5 2
Earliest ES 0 3 11 3 21 22 7 23
EF 3 11 21 7 22 23 12 25
Latest LS 0 3 11 14 21 22 18 23
LF 3 11 21 18 22 23 23 25
Float TF 0 0 0 11 0 0 11 0
FF 0 0 0 11 0 0 11 0
Resources Per Day 4 7 4 5 4 4 5 6 Total projects man days
Tota Resource 12 56 40 20 4 4 25 12 173
Figure (5.7) presents the time schedule and the number of employees if the plan is presented by the early start (i.e., all activ- ity starts in its first starting time). At the bottom of the schedule another option is presented of launching all the activities which are not on the critical path at the latest starting time. In our example, this is represented by activities 400 (installing the piping) and 700 (connecting the piping).
In the first case, the maximum number men on site will be 12, whereas under the second option, using the latest start, the maxi- mum will be 9 persons. Therefore, a decision needs to be made on whether to use the total float or free float to achieve the proj- ect target. In normal cases, it is preferable to keep the number of laborers on site as few as possible consistent with safety standards and project requirements, since, if the number of onsite laborers is increased, the probability of accidents and injury may increase.
A similar consideration arises with siting laborers in remote areas such as those in which oil and gas projects are conducted:
accommodations have to be provided by the company that may be onsite or nearby but in any case add to the project's ongoing operating costs. If the optimum number of onsite personnel can be minimized, it will help rein to in these costs. (In some cases of this kind, there may be fiurther constraints, e.g., if the client can provides accommodation for only 10 persons per day near or on the site.)
When it comes ot staffing levels in the engineering design office, it is important for maintaining the project's output quality that the work load is distributed so as to maximize the distribution of work and working time to full-time engineering staff, while minimizing the hiring of part-time, or six-month-contracts-at-a-time, engineer- ing staff. Too much part-time work eventually undermines overall project quality, so an appropriate distribution of work loads can be highly beneficial.
Figures (5.8) and (5.9) present the distribution of the resources in two cases, and the harmony of resources distribution is visible if we use the latest start activity as discussed before.
It is worth mentioning here that, in the case of large projects, a meeting be held between a representative of the owner, the consul- tant, and the contractor. In this meeting, the contractor should define the personnel and equipment that will be found at the site in accor- dance with the schedule plan. In this meeting all the representative engineers should reach a working agreement about the allocation
Activity Mobilization Excavation Pouring cone. Mech. packg Grouting Comm &start u[ Install piping Connect piping Sum Install piping Connect piping Sum
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25 6 6 Figure 5.7
Resources unit 12
8 4 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 1516 17 18 19 2021 22 23 24 25 Days
Figure 5.8 Resources distribution in first case.
Resources unit 12
8 4
0 1 2 3 4 5 6 7 8 9 10 1112 13 14 1516 17 18 19 20 2122 23 24 25 Days
Figure 5.9 Resources distribution by latest plan.