Construction Schedule Techniques
There are many ways in the construction industry to represent and create construction schedules techniques. Which one is the best for you? We will explain briefly four alternatives that you can use depending on the project requirements and difficulties.
Construction Schedule: Bar Charts
Bar Charts are the most simple and easiest way to produce a scheduling form in the construction industry. It is widely used due to its simplicity and multiple adaptations to numerous events. A bar charts is formed with a list of activities, specifying the start date, duration of the activity and completion date of each activity, and then plotted into a the project time scale. The detailed level of the bar chart will depend on your project complexity and the intended use of the schedule.
A variation of the bar chart schedule, is the linked bar chart. Using a linked bar chart, the activities and subsequent items are linked with arrows and lines, specifying the sequence and order of preceding activities. The previous activities are linked one to another to demonstrate that one activity must be completed before the other activity can start.
Bar charts are useful and commonly used to detect the amount of resources needed for one particular project. Adding the resources vertically will produce what is called the resource aggregation. The purpose of this aggregation is to estimate the work production and establishing estimates for man-hour and equipment needed.
Construction Schedule: Critical Path Method
This process is more elaborated and detailed than the previous one. With a large list of activities, each activity is then linked to previous and subsequent activities, specifying that each activity has at least another one that must be completed prior to starting the preceding one. With the Critical Path Method, calendar days are established and activities are assigned with an early date, first date that an activity can start; late start, specifying the last possible date that this activity must be started to avoid delays in the overall construction process; early finish, the earlier date that the proposed activity will be completed; and the late finish, that is the last date the activity must be completed without affecting the start of the next one, and subsequently affecting the entire construction schedule. The steps in producing a network are:
- Listing of activities
- Producing a network showing the logical relationship between activities.
- Assessing the duration of each activity, producing a schedule, and determining the start and finish times of each activity and the available float
- Assessing the required resources.
Construction Schedule: Line of Balance
This process is a planning technique for repetitive work. The essential procedure for this scheduling technique is to allocate the resources needed for each step or operation, so the following activities are not delayed and the result can be obtained. The principles employed are taken from the planning and control of manufacturing processes greatly modified by E. G. Trimple. This process is usually applied in the construction work and more specific in road construction.
Construction Schedule: Q Scheduling
Q. Scheduling is quantitative scheduling, in the context that quantities to be executed at different locations of the construction project form the elements of the schedule. Also Q. Scheduling is Queue Scheduling in the context that trades pass through the different segments of the project in a queue sequence. No interference between two activities is allowed at the same location. It is derived basically from the Line of balance technique with some modifications to allow for the non repetitive models that are characteristic of the majority of construction projects.
The Q Scheduling is a new technique, though getting rapid popularity among contracting firms. It is the only scheduling technique that reveals a relation between the sequence of doing a job and the cost to be incurred. The Q schedule is similar to the Line of Balance with some modifications, to allow for a varying volume of repetitive activities at different segments or locations of the construction project, thus the model produced is closer to reality.