The construction industries should form accurate construction schedule techniques to ensure the effective coordination of work.
The mostly used scheduling techniques in construction project is described below :-
Bar Charts and Linked Bar Charts
Network Analysis and Critical Path Method
Line of Balance
Q Scheduling
Bar Charts and Linked Bar Charts
Bar chart is nothing but a simple graphical method of scheduling activities in construction management to commune between management and employees about the accomplishment of the work on a given day. It is also known as Gantt Chart. Bar charts can be generated by a variety of software programs.
A typical Bar chart contains activities with the start, duration and finish of each activity exposed as a bar plotted to a time scale. The level of detail of the activities depends on the proposed use of the schedule.
The bar charts are also utilized for computing the necessary resources for the project. To put in the resources to every activity and total them vertically is known as resource aggregation. In order to estimate the work content regarding man-hours and machine hours, bar charts and resource aggregation charts are very much useful.
The linked bar chart illustrates the links between an activity and its preceding activities which should be completed prior the starting of this activity.
The bar chart includes a two dimensional chart. The x-axis of the chart represents the project timeline and y-axis contains a list of specific activities to be accomplished for completing the project. These activities are typically listed in order of earliest start on the project. The bar chart consists of bars which demonstrate the planned (and/or actual) start and end times for each task. In view of the fact that the tasks are generally organized from earliest to latest, most bar charts illustrate a pattern of bars that commence in the upper left of the chart and go on to bars that complete the project displayed in the bottom right of the chart.
Among the various methods available the least expensive methods is to employ the spreadsheet software programs.
Activities are listed on the Bar Chart in to the sequence that the activity should be completed. "Activity 1" becomes visible at the top of the y-axis. The length of Activity 1 is comparative to the required time for finishing the task.
Given below some checklist for generating effective Bar Charts:
Label the x-axis in working days or weeks
Use "ticks" to show working weeks or months
Y-axis shows the start of the project at time = 0
Skip lines between bars
Print the activity name above each bar, if possible
Free Online Bar Chart Construction Schedule
GNetwork Analysis and Critical Path Method
Network analysis produces more pragmatic models of the proposed work with its logic diagram. The following steps are applied for producing a network:
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
Now-a-days two popular forms of network analysis namely activity on the arrow and activity on the node are available in construction management practice. The latter now frequently described a precedence diagram. Each of these approaches offers virtually the same facilities and it seems largely a matter of preference which is used.
A critical path method refers to a network of events. Here e one of them linked to the following activities. Each activity is represented as a node on the network, and connecting lines are drawn to represent the time schedule to complete that activity.
The Critical Path Method schedule comes up with all work specified in the Contract Documents as well as all probable activities of subcontractors, vendors, suppliers and all other parties related with construction project.
Through the Critical Path Method(CPM), calendar days are ascertained and activities are allocated 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.
A critical path method represents a graphical view of the project. It will help you to have the required time for accomplishing an activity and find out the activities that may be critical if not performed within the specified time of a project.
A critical path method schedule must be completed using the following steps:
Identify the activities
Determine the sequence of the activities
Producing a network showing the logical relationship between activities
Assessing the duration of each activity, producing a schedule and Enter the completion time for every activity listed on step 1
Identify the critical path or the longest possible path to complete all activities
One important and valuable component is the CPM update progress, allowing to track closely the performance and time used to complete the activities
The network of activities should start at the time of all activities have been defined and interdependence of activities has been analyzed. All critical work sequence is linked with logical coordination and planning requirements. The CPM format must be based on calendar days as their main planning unit. Working days should be avoided when planning or preparing a critical path method schedule.
Line of Balance
The Line‐Of‐Balance Scheduling Technique(LOBST) can be termed as a linear scheduling method that permits the balancing of the operations such that each activity is continuously and efficiently performed in each consecutive unit.
Line of Balance scheduling technique (LOB) is nothing but a planning technique to allocate the resources to restrain the repeated operations for a project.
The line of balance technique is useful for construction work mostly to house building, jetty work, road works and high-rise construction. Consequently the Line-of-Balance diagram is an essential communication and productivity analysis tool for projects that have repetitive work areas.
In the context of construction projects, the LOB technique offers two main advantages:
It gives the ability to the project managers to verify whether they will be able to meet the schedule in the middle of a project, if they continue working as they have been.
It exposes process bottlenecks, allowing the project manager to focus on those points responsible for slippage.
Arrow and Precedence Diagramming are capable to model these types of schedules efficiently. The Line-of-Balance (also known as the Vertical Production Method) is a graphical technique to be applied together with Arrow or Precedence Diagrams.
In the Line-of-Balance diagram, the x-axis represents (as in the bar chart) the timeline of the project. The y-axis identifies the work areas that define the project. The blank chart is the starting point for the Line-of-Balance schedule.
Q Scheduling
Q. Scheduling is known as quantitative scheduling. In this technique quantities are accomplished at different locations of the construction project form the elements of the schedule. Q. Scheduling trades pass all the way through the diverse sections of the project in a queue sequence. No intervention between two activities is permitted at the same location. It is obtained mainly from the Line of balance technique making some amendments to allow for a varying volume of repetitive activities at different segments or locations of the construction project.
The Q Scheduling is the solitary scheduling technique that exposes a relation among the sequence of performing a job and the incurable cost.
Posted by Rajib Dey
Business Development
Global Associates
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