Logic Link Categories: Use in Forensic Planning and Effective
Construction Programme Management
By Ian Gunton, Director and Planning Consultant, Construction Navigation Services Ltd.
Logic Links are a fundamental part of any programme. They provide the meaning, structure and relationship between the activities listed. A programme without links has no meaning.
As the work progresses, it is essential to record the as-built, progress, additional work and logic link changes. The programme then remains ‘fluid’ and mirrors the project’s performance at any given point in time.
Asta Powerproject allows the planner to create link categories, which define the purpose of the link and highlight it as an existing, redundant or new link.
It is vital that all the redundant and new logic links remain visible in the updated programme. The ability to record these changes and retain the history and development of the programme is invaluable should a dispute arise. It also enables highly effective communication between the parties involved in the project.
These link categories can be created in the ‘Link Category’ library as shown in Screenshot 1 below.
The project is available at the end of this page. Simply select, then copy & paste the link categories into your own generic programme, or create them yourself.
The categorising of a link using different colours, line styles and arrow heads within the ‘Link Category’ library helps to define a link and provides the reader with an understanding of what the link is doing. However, it is important not to have too many link categories as this would overcomplicate the programme.
Open Screenshot 1: Library Link Category
The link categories are:
- Construction Link. This defines a link as a construction link, where an activity such as Foundation links to another activity, Walls.
- Design/ Info Link. This defines a link as a design information link, where the off-site design/ information of the Foundation links to the on site activity building the Foundation.
- Resource Link. This defines a link as a resource link, where the resource from one activity such as Walls 1 links to another activity, Walls 2.
- Safety Link. This defines a link as a safety link, where one activity is kept apart from another activity due to a safety issue such as confined space or overhead working etc.
These simple link categories provide the reader with an understanding of what the link is doing within the network.
Open Screenshot 2: Link Categories within a baseline programme
To allow full traceability as the project and programme are progressed and updated, the following link categories are also created:
- Construction Link (N). This defines the link as a construction link ‘New’. Where changes are made in the project’s progress, as-built and/or re-sequencing of the programme, these new links are added to create the new network on which to reschedule. This will then reflect the true position and status of both the project and programme at the update period. Any new activities and/or additional work added to the programme will have these new links. To define the link, all that has changed is the arrow heads. The line style and colour remain as per the construction link category.
- Construction Link (R). This defines the link as a construction link -‘Redundant’. Where a link has become redundant through changes made in the project’s progress, as-built and/or re-sequencing of the programme, the link is re-categorised as redundant. To define the link, all that has changed is the colour of the line and arrowhead to grey, so that the link becomes less visible when viewed in the network.
These new and redundant link categories are also created for the Design/Info, Resource and Safety link categories.
When a programme is updated and progressed with as-built data, the re-sequencing of the logic links can be shown as detailed in Screenshot 3 and 4 below. Screenshot 3 illustrates a logic link which has been re-categorised as redundant. Screenshot 4 shows a new logic link which has been created to establish a new network based upon the current thinking and decisions made.
To categorise or re-categorise a link, right click over the link and select ‘Properties’. The property box appears as shown below. Click on the ‘Link category’ and a drop down list appears. Select the link category from the list. Comments can be added at the bottom to record what has been done and when.
Open Screenshot 3: Redundant Link Category
Open Screenshot 4: New Link Category
For the network to reschedule correctly, the redundant link categories need to be turned off. Select ‘Tools’ then ‘Reschedule’ and then the ‘Options’ Tab. Then select and tick the redundant link categories within the ‘Ignore link categories’ list section as shown in Screenshot 5 below. (Be sure to select all the redundant link categories). The network will now ignore the redundant links and reschedule using the original and new logic links.
Open Screenshot 5: Rescheduling Link Categories
It is important to maintain the original baseline activities and not to delete any activity or logic link. The above method enables the reader to understand what has changed. It also maintains a record as the programme is progressed and updated.
Categorising of links provides the reader with an understanding of what each link is doing. The recording of ‘logic link changes’ against the original baseline programme as the programme progresses provides powerful ‘transparent’ information.
Asta Powerproject enables this, allowing the programme to remain fluid throughout the project’s life.
The same methodology above can be used for retrospective forensic planning and timeslice analysis. If you would like further information please contact us at www.cnsplanning.com.
Ian Gunton,
Director and Planning Consultant,
Construction Navigation Services Ltd.
Download the Asta Powerproject project files - get hold of the project that the above screenshots are based on here.
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